The secret to lifelong human happiness is simple: Stay married.

I pay particular attention to the very young and the very old.

I like children because they have not yet learned how to lie comprehensively. Abstract deception is one of the sine qua non attributes of the fully-human state of consciousness – and yet another thing dancing bears can never do – but it’s my least favorite arrow in the conceptual quiver.

And I attend to the elderly because they embody the lifelong practical consequences of habituated probity or deceit. Nature is just, so time wounds all heels, but time also seasons goodness into sweetness.

Can there be a single, easily-implemented key to lifelong happiness?

Surely the answer is yes: Love your self.

But to do that, as we’ve noted, you must make your self lovable, fueling your mind with the hope that your hard work will pay off.

Can you do that alone?

For a while, as a young adult, but the evidence of the elderly argues that you can’t do it forever.

Perhaps I’m conflating unlike things, since the fate of the solitary old person was generally sealed by too much deceit, not too much solitude. Even so, the overwhelming number of the very happy old people I meet are very happily married.

Yesterday I met a couple who take the prize for lifelong happiness together.

They were walking side-by-side holding hands, which only children, the newly-romantic and the happily-coupled do. But they were also connected in another way: She had an oxygen-supplementation line – and he was carrying her tank.

A simple enough thing – chivalry or common courtesy, certainly no huge burden. But it was marriage near the end of life in a way you would not have seen it when those two were younger: They are there for each other, and they cannot be apart as long as they are connected by that skinny, transparent oxygen line.

When you are young, you think you can get away with lying to yourself, but this is just because the consequences of your deception have not caught up with you yet. Older people can lie, but they cannot hide their emotional scars.

When I see old people out in the world, I will often say, “Keep at it. There’s a wheelchair behind you. If you slow down, it’ll catch you.” The reality of human life can be better than that – at the end and throughout your life – or it can be much, much worse.

Keep loving, and love harder, more honestly, every day. If you don’t there could be nothing but an empty room ahead of you, a jail cell without the bars.

The actual, practical, day-to-day solution to the problem of lifelong human happiness is simple: Stay married. When the music stops – and it will – you’ll have a place to land.